The present invention relates generally to an automated conveyorized transport system having an endless chain moved under power through track sections suspended above a rail to propel free traveling trolleys along the rail and, more particularly relates to an improvement in such a system wherein means are provided for expanding adjacently disposed sections of track relative to one another thereby tensioning the endless chain travelling in these track sections.
In automated transport systems of the type which this invention is concerned, an endless chain travels within a channel formed by a series of track sections positioned relative to one another in an end to end manner such that the endless chain as it moves through the channel formed by the track sections, propels trolleys from one position in the system to another. These systems are typically found in production facilities in which work pieces are carried by trolleys between a series of work stations where various work operations are performed on the work pieces or at which locations the work pieces may be moved for storage for transportation later in time. One such type of transport system is disclosed in U.S. Pat. No. 4,712,485 issued to Roland P. Nimark on Dec. 15, 1987, and which patent being currently assigned to the assignee of the present invention.
The endless chain employed in the aforesaid reference is driven by a rotary power source, such as an electric motor having a rotary drive member, which chain is moved relative to the power source by engagement of individual links with the rotary drive member. As such, it is important that individual links of the chain be maintained in a linear relationship with one another to avoid jamming problems which may occur in the chain as it engages and couples with the rotary drive member. In addition, it is desirable to maintain tension in the chain as it moves through the track sections at a rapid velocity so as to avoid undesirable noise generated by rattling which may otherwise be generated by the chain as a result of slack which may exist in the loop.
Attempts have been made to remedy this problem but, these attempts have unfavorably resulted in damage occurring to the track sections. Hitherto, tensioning of the chain was accomplished by spreading adjacently disposed ends of track section in a manner such that an operator loosened connecting plates bridging the opposed track sections with one another and then inserted a prying instrument, such as an enlarged screw driver, between the ends of each track section thereby prying apart the track sections to create a slight gap and thereafter resecured the previously loosened connecting plates while simultaneously holding the prying instrument in place to maintain the gap obtained by the prying action. This method of tensioninq the endless chain while being awkward, furthermore resulted in the ends of the track sections being deformed by the inserted instrument thereby disrupting the otherwise previously existing smooth interior housing through which the endless chain travels.
Accordingly, it is an object of the present invention to provide a track expander usable in a track of the aforesaid type to tension an endless chain travelling within the track by spreading adjacently disposed track sections relative to one another by means of an expander cooperating with a splice connecting adjacent track sections.
It is yet another object of the present to provide a method by which track sections may be spread one relative to the other to create tension in an endless chain travelling through the track sections.